Throat-plate for double-chain-stitch machines.



r A. H. DE VOE. THROAT PLATE FOR DOUBLE CHAIN STITCH MACHINES.

- APPLICATION FILED DEC. 1. 19.16. JlfifififiQ Patented Jan. 22, 1918.

. barren 1 sratrns Parisian onnr Jilrl o ALBERT H. DE VOE, OF WESTFIELD, NEW JERSEY, ASSIGNOR TO THE SINGER MANU- FAGT'URING COMPANY, A CORPORA'IIQN OF NEW JERSEY.

THROAT-PLATE FOR DOUBLE-CHAIN-STITGH MACHINES.

fi,25ei,2iet.

Specification of Letters'Patent.

Patented J an. 22, 191%.

Application filed December 1,1916. Serial No. 134,253.

To all whom it may concern:

Be it known that I, ALBERT H. DE Von, a citizen of the United States, residing at Vestfield, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Throat-Plates for Double-Chain-Stitch Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to sewing machines of the kind making a double-thread chainstitch.

In machines employing a needle and athread-carrying looper or a plurality thereof the needle in its descent enters a triangle formed by the back of the looper, the thread extending from the eye of the looper to the previous stitch and the needle-loop on the looper. Various devices have heretofore been used for insuring the entrance of the needle into this triangle. My invention consists in a simple and efiective means for holding the needle-loop on the looper out of the path of the descending needle comprising a bar or a plurality of bars located beneath the throat-plate of the ma chine in the rear of the needle and across the elongated needle-hole. As the fabric is fed forward to enable the needle to puncture it a stitchlength from the previous puncture, the upper extremities of the limbs of a needle-loop on the looper are carried forward with the fabric while the looper, which is backing out of the needle-loop at this time, carries that portion of the needle-loop which is around the looper in the opposite direction because the looper is either suitablv bulged or offset in the region of its beak. The limbs of the needle-loop upon the looper are thus snubbed or tightened across the bar which, because of its inclination to the line of feed, deflects both limbs of the needle-loop to one side of the path in which the needle is reciprocated.

My invention also consists in further details of construction which will appear in the description of the embodiment of my invention illustrated in the accompanying drawings, in which Figure tie a plan view of the throat-plate; Fig. 2 is a perspective view of the bottom thereof; Fig. 3 is a plan view of a needle-hole showing the relative location of the needle, the looper and limbs of he eads when the needle is about to enter the looper triangle; and Fig. t is longitudinal section of the throat-plate through the same needle-hole.

in the drawings a needle is indicated at l and a thread-carrying looper at- 2 which may be actuated by any suitable mechanism, of which the prior art discloses a great variety. The looper may be, as shown, inclined to the line of feed at any desired angle or may be moved in a plane parallel with the vertical plane of feed. The blade portion of the looper is offset as indicated at 8 to hold the needle-loop back upon the looper when it is retracted.

A throat-plate isuitably cut away as at 5 to permit feed-dogs shown at 5 to be engaged with the fabric is provided with an elongated needle-hole 6. Across the needlehole beneath the throat-plate is located a bar 7 which is secured in any suitable manner thereto preferably as shown, being formed integral with the plate. This bar has its front upper edge rounded as at 8 to prevent breaking the limbs of the needle- .loop which are strained across it at certain times in a stitching cycle. As clearly shown in Fig. 3 the front wall of the bar 7 constitutes the rear wall of the needle-hole and is inclined to the line of feed so that when the needle-loop is tightened across the bar by the movement in opposite directions of the fabric and the looper, the limbs of the needle-loop will be deflected out of the path of the descei'iding needle to insure the entrance of the needle into the triangle formed by the looper-blade, the looper-thread leading from the work to the eye of the looper and the needle-loop on the looper.

Vhile I have described the mechanism as consisting of a single needle, looper and bar, it is quite obvious that a plurality of needles 1, loopers 2 and bars 7 may be used.

It is to be understood that I do not wish to be limited to the plane in which the looper moves in entering and withdrawing from the needle-loops as the coaction of a bar and looper during the feeding of a fabric will be the same, with possibly a difference of degree, whether the looper moves parallel with the feed or at an angle thereto.

Having thus set forth the nature of the invention, what I claim herein is 1. In a multiple thread chain-stitch machine, in combination, work-feeding mechanism, a needle, a thread carrying looper,

and a throat-plate provided with a needlehole and having a Wall located in rear of the needle-hole and inclined to the line of seamforniation whereby in the formation of stitches the limbs of a needle-loop are deflected from the path of the needle.

2. In a two-thread chain-stitch machine, in combination, a feed-dog, a rectilinearly reciprocating needle, a thread-carrying looper, and a throat-plate provided With a needle-hole defined by Walls of which one crossing the needle-hole in rear of the needle in the line of feed is straight for a distance substantially greater than the diameter of the needle and is so arranged with respect to the line of feed that limbs of a needle loop on the looper are deflected out of the path of the descending needle to increase the size of the looper triangle when the looper is retracted during the feeding of the fabric.

3. In a throat-plate provided With one or more elongated needle-holes, a bar-like memher having a front Wall or face arranged across each elongated needle-hole at an'inclination to its length, "said front Wall or face terminating a substantial distance below the upper face of the throat-plate.

In testimony whereof, I have signed my name to this specification.

- ALBERT H. DE VOE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

